The Lucy Thermal Emission Spectrometer (L'TES) Instrument

Area of Science:

• Planetary Science
• Astrophysics
• Spectroscopy

Background:

• The Lucy mission targets Trojan asteroids, necessitating remote sensing capabilities.
• Understanding asteroid thermophysical properties is crucial for planetary formation studies.
• Previous instruments like OTES on OSIRIS-REx provide a foundation for new mission hardware.

Purpose of the Study:

• To detail the design and capabilities of the Lucy Thermal Emission Spectrometer (L'TES).
• To outline the instrument's ability to remotely measure thermophysical properties of Trojan asteroids.
• To confirm the instrument's readiness and performance through calibration and initial space data.

Main Methods:

• Utilizing a Fourier Transform spectrometer (FTS) covering 5.71-100 μm.
• Employing a Cassegrain telescope with a 15.2-cm aperture.
• Incorporating a DLATGS pyroelectric detector and a metrology interferometer for precise control.

Main Results:

• The L'TES instrument is a build-to-print copy of the OTES instrument.
• It offers variable acquisition times (0.5, 1, 2 seconds) for different spectral resolutions.
• Radiometric precision is ≤2.2 × 10⁻⁸ W cm⁻² sr⁻¹/cm⁻¹, with absolute temperature error <2 K for >75 K scenes.

Conclusions:

• L'TES is a fully characterized instrument ready for its mission objectives.
• Initial space data confirms the instrument's radiometric and spatial performance.
• The instrument is poised to deliver key thermophysical data on Trojan asteroids.